On Fri, Aug 19, 2022 at 6:00 PM Limonciello, Mario <mario.limonciello@xxxxxxx> wrote: > > On 8/19/2022 10:44, Karol Herbst wrote: > > On Fri, Aug 19, 2022 at 4:25 PM Mario Limonciello > > <mario.limonciello@xxxxxxx> wrote: > >> > >> 3 _OSI strings were introduced in recent years that were intended > >> to workaround very specific problems found on specific systems. > >> > >> The idea was supposed to be that these quirks were only used on > >> those systems, but this proved to be a bad assumption. I've found > >> at least one system in the wild where the vendor using the _OSI > >> string doesn't match the _OSI string and the neither does the use. > >> > >> So this brings a good time to review keeping those strings in the kernel. > >> There are 3 strings that were introduced: > >> > >> Linux-Dell-Video > >> -> Intended for systems with NVIDIA cards that didn't support RTD3 > >> Linux-Lenovo-NV-HDMI-Audio > >> -> Intended for powering on NVIDIA HDMI device > >> Linux-HPI-Hybrid-Graphics > >> -> Intended for changing dGPU output > >> > >> AFAIK the first string is no longer relevant as nouveau now supports > >> RTD3. If that's wrong, this can be changed for the series. > >> > > > > Nouveau always supported RTD3, because that's mainly a kernel feature. > > When those were introduced we simply had a bug only hit on a few > > systems. And instead of helping us to debug this, this workaround was > > added :( We were not even asked about this. > > My apologies, I was certainly part of the impetus for this W/A in the > first place while I was at my previous employer. Your comment > re-affirms to me that at least the first patch is correct. > Yeah, no worries. I just hope that people in the future will communicate such things. Anyway, there are a few issues with the runpm stuff left, and looking at what nvidia does in their open driver makes me wonder if we might need a bigger overhaul of runpm. They do apply bridge/host controller specific workarounds and I suspect some of them are related here as the workaround I came up with in nouveau can be seen in 434fdb51513bf. But also having access to documentation/specification from what Nvidia is doing would be quite helpful. We know that on some really new AMD systems we run into new issues and this needs some investigation. I simply don't access to any laptops where this problem can be seen. > > > > I am a bit curious about the other two though as I am not even sure > > they are needed at all as we put other work arounds in place. @Lyude > > Paul might know more about these. > > > > If the other two really aren't needed anymore, then yeah we should just > tear all 3 out. If that's the direction we go, I would appreciate some > commit IDs to reference in the commit message for tearing them out so > that if they end up backporting to stable we know how far they should go. >
